Automatic control for maintaining constant density in hydraulic classifier



Oct. 29, 1957 w H HISLE 2,811,257

AUTOMATIC CONTROL FOR MAINTAINING CONSTANT DENSITY IN HYDRAULIC CLASSIFIER Filed my 14, 1954 s Sheets-Sheet 1 INVENTOR. WILL 14M H. H/SL E,

BY WZ WZM W wAQaMb/awz.

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Oct. 29, 1957 2,811,257

W. H. HlSL AUTOMATIC CONTROL FOR MAINTAINING CONSTANT DENSITY IN HYDRAULIC CLASSIFIER Filed May 14, 1954 3 Sheets-Sheet 2 INVENTOR. WILL/AM H. H/SLE,

Filed May 14, 1954 Oct. 29. 1957 w. H. HISLE 2,811,

AUTOMATIC CONTROL FOR MAINTAINING CONSTANT DENSITY IN HYDRAULIC CLASSIFIER 5 Sheets-Sheet 3 FIG. 4.

' INVENTOR. wu. L 1AM H. -H/SL E,

United States Patent AUTOMATIC CONTROL FOR MAINTAIN- lNG CONSTANT DENSITY IN HYDRAU- LIC CLASSH IER William H. Hisle, Nye, Mont, assignor to American Chrome Company, San Francisco, Calif., a corporation of Nevada Application May 14, 1954, Serial No. 429,949

2 Claims. (Cl. 209--500) This invention relates to classifiers, and more particularly to an improved hydraulic classifier for separating minerals or the like and sorting mineral particles by size.

A main object of the invention is to provide a novel and improved automatic classifier of the hydraulic type, said classifier being simple in construction, being arranged to maintain a constant density in the respective classifying chambers thereof even though the character or quantity of the feed material varies, and being arranged to automatically vary the supply of hydraulic water to the classifying chambers thereof in accordance with variations in the density of the material in the respective compartments of the classifier.

A further object of the invention is to provide an improved hydraulic classifier for separating minerals or the like, the device being provided with means for automatically varying the supply of water to the respective classifying chambers of the device in accordance with variations in density in the respective chambers, and at the same time maintaining the rate of discharge from the classifier substantially constant so that the classified or sized material is discharged from the chambers at a substantially constant rate, the improved classifier being relatively inexpensive to construct, being reliable in operation, and being easy to adjust.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a fragmentary top plan view of an improved classifier constructed in accordance with the present invention.

Figure 2 is a fragmentary side elevational view, partly in vertical cross section, of the classifier illustrated in Figure 1.

Figure 3 is a transverse vertical cross sectional view taken on the line 33 of Figure 1.

Figure 4 is an enlarged cross sectional detail view taken on the line 44 of Figure 3.

Figure 5 is an enlarged cross sectional detail view taken on the line 55 of Figure 2.

The principle of hydraulic classification or sizing of solids involves passing a ground pulp of the solids and water through a tank which is divided into a number of compartments. Each compartment is provided with an outlet for discharging a portion of the feed entering that compartment. The first compartment discharges the coarsest and heaviest particles, with each succeeding compartment discharging the coarsest and heaviest of the remaining particles. The discharge of material from each compartment is controlled by varying the size of the discharge opening and by maintaining a constant density in the associated sorting column of the classifier or sizer. The density is controlled by varying the amount of Water admitted into the associated column or sorting chamber, for example, by admitting the water through a perforated plate that separates the sorting column and a hydraulic chamber located therebelow.

In adevice according to the present invention, the control means for the classifier includes two controllable features, namely, an adjustable discharge valve for each classifying chamber, which in the embodiment of the invention described hereincornprises a plug valve arranged so that it may be manually adjusted from the top of the classifier, whereby the rate of discharge from each classifying chamber may be adjusted. A second controllable feature comprises means for controlling the density of the pulp in each of the classifying chambers, by regulating the amount of water admitted to the hydraulic chamber below the associated classifying chamber, and in the device of the present invention, this admission of hydraulic water is controlled in accordance with variations in the density of the material in the sorting column inthe classifying chamber.

Referring now to the drawings, 11 generally designates an improved classifying device according to the present invention, said device comprising a tank 12 having the feed inlet portion 13 at one end thereof. Secured in the tank are a plurality of spaced vertical partitions 14 which divide the tank into successive compartments over which feed material admitted into the inlet portion 13 of the tank may fiow and may deposit particles to be classified in accordance with size, the particles being of like specific gravity, so that the largest particles will deposit in the compartments located more closely adjacent to the inlet portion 13 of the tank and the smaller particles will be deposited in the compartments remote from the inlet portion 13.

The compartments defined between the transverse vertical partition members 14 are designated at 15, and each compartment has secured in its lower portion a perforated plate member 16 defining a hydraulic chamber 17 therebelow.

As shown in Figure 3, the upper portion of the tank comprises the enlarged channel 18 which extends from above the compartment 15 adjacent to the feed inlet portion 13 of the tank to the opposite end of the tank, and discharges into a drain conduit 19. The channel 18 increases in cross sectional area from the left end of the tank to the drain end thereof, as viewed in Figure 2. The channel 18, of course, extends over the respective compartments 15 to thereby connect the upper portions of the compartments, whereby liquid containing material to be classified may flow over the respective compartments. The material to be classified is contained in the feed material admitted into the inlet portion 13 of the tank, for example, a ground pulp of the solids to be classified and water.

Each compartment 15 is provided with a vertical discharge conduit 21 extending through the perforated plate 16 and the bottom wall 22, as shown in Figure 2, the lower portion of each discharge conduit 21 being provided with the annular valve seat 23 cooperating with a plug valve element 24 for adjusting the rate of discharge of material through the conduit 21. The plug valve 24 is carried on the lower end of a valve rod 25 which extends vertically through the compartment and through the top of the tank, the valve rod being provided at its upper end with an adjusting wheel 26 which threadedly engages the rod and which is employed to adjust the position of the rod vertically, whereby the plug element 24 may be adjusted vertically relative to the annular valve seat 23.

As shown in Figure 5, the discharge opening defined between the plug valve 24 and the annular valve seat 23 is kept open and further controlled by the admission of a small stream of water into the space adjacent the plug element 24 through a conduit 27 opening into the discharge conduit 21 just above the annular valve seat 23, as illustratedin Figure 5.. The conduit 27 is connected to a Water supply header 28, as shown inFigure 3, and includes a manually operated valve 29 for adjusting the amount of water admitted into the discharge conduit through the conduit 27. 7

One side of each of the hydraulic chambers 17 is connected to the header 23 by a conduit 3b which includes manually controlled valve 31. As shown in Figures 4 and 5, the valve 31 may comprise a conduit section 32 of flexible material on which is mounted a rectangular frame 33 having the respective side posts 34, 34 on which is slidably engaged a valve plate 35 which is arranged parallel to the frame member 36. Rotatably connected to the plate 35 at a boss 37 thereon is the threaded valve stem 33 which extends threadedly through the frame element 39 at 46, as shown in Figure 4, the stem 33 being provided with the handle 41 for rotating the stem. As will be readily apparent from Figure 4, when the stem 38 is rotated, the plate 35 exerts clamping force on the intermediate portion of the flexible conduit 32, thereby decreasing its internal cross sectional area, and thereby decreasing the rate of flow of water therethrough. Thus, the valve 31 may be adjusted to provide a desired constant supply of Water to the hydraulic chamber 17 from the header 28.

Connected to each hydraulic chamber 17 opposite the conduit 30 is another conduit 42 which contains a motorized valve 43, the conduit 42 being connected to the header 28 through the valve 43 and a connecting conduit 44, as shown in Figure 3. The motorized valve 43 may be of any suitable commercial type which is electrically controlled, for example, may be a valve similar to model KZQOB manufactured by the Minneapolis-Honeywell Regulator Company, which is a single-seated globe type valve assembly having the globe valve portion 45 and the electrical control portion 46. The electrical control portion 46 is similar to the model M904E Modutrol motor, manufactured by ll linneapolis-Honeywell Regulator Company and controls the globe valve portion 45 through a suitable linkage such as, for example, a Q601B linkage manufactured by the above mentioned Minneapolis-Honeywell Regulator Company.

The motor device 46 is operated by a pressure controlled device 47, for example, by a model L91D Pressuretrol manufactured by the above mentioned Minneapolis- Honeywell Regulator Company, the device 47 being connected to the motor 46 by a suitable cable 45. The pressure responsive device 47 is connected by a conduit 49 to a depending hydrostatic tube '59 suitably secured in and extending through the top of the tank 12, as shown in Figure 3. exposed to the material in the compartment 15, and the pressure in the tube varies in accordance with variations in the density of the column of material deposited in the ch amber. The motorized valve 43 is adjusted so that more or less water will be admitted into the hydraulic chamber 17 in accordance with increases or decreases in said density, the result being to maintain a substantially constant density of material in the sorting column deposited in the compartment 15.

In operation of the device, hydraulic water is admitted into each chamber 17 from the hydraulic header 28 by means of the manually adjusted valve 31 and the automatically controlled valve 43. As the pulp passes through the classifier, the heavier or larger particles settle against ascending currents of water rising from the hydraulic chamber 17 in each compartment through the perforated plates 16. As the particles of material cannot pass through the plates 16 at all points thereof, a bed of material is built up in each chamber. A portion of the material is discharged through the associated discharge conduit 21 at a rate determined by the setting of the valve plug element 24 therein. As the material builds up in the sorting column in the chamber, the density of the teeter bed increases, and this change, or other change in density, results in a change in the pressure in the hydrostatic tube The lower end of the hydrostatic tube 50 is 50 of the associated chamber which is transmitted to the pressure responsive device 47. The pressure responsive device 47 may be set to operate at any desired pressure, and through a potentiometer therein, operates the motorized valve 43, namely, operates the motor device 46, which in turn operates the valve element 45 through the linkage thereof, opening or closing the valve element 45, as re quired. Thus, the control element 47 operates the motorized valve device 43 to maintain a desired density in the sorting column of the associated chamber 15. If the density rises, the valve element 45 opens and more water enters the hydraulic chamber 17, thereby reducing the density. If the density drops, the valve element 45 closes and the flow of water is decreased, causing the density in compartment 15 to rise to the desired level.

Thus, the density in the respective compartments 15 is maintained substantially constant, and the rate of discharge from each of the compartments is also maintained substantially constant at a rate determined by the adjust ment of the respective plug valve elements 24.

It will be understood that prior to actual operation, as above described, the tank is first filled with water to the level of the overflow Weirs in the tank, all discharge valve elements 24 being in closed positions. The potentiometer arm of each motor device 46 is then manually moved to a point which causes the motor element thereof to hold its valve element 45 substantially one-half opened. The current to the motor device 46 is then shut oil? so that the valve 45 remains in this position until subject to automatic control.

Feed material (ground ore or rock with water), is then admitted to the classifier. The heaviest and% or coarsest particles settle in the first compartment and so on along the respective compartments of the tank. The manually operated valves 31 are opened to the point where full teeter is observed through the inspection windows, shown at 60, of the compartments. The full teeter" condition exists when there is just visible agitation or suspension of the coarsest particles, giving a dense but fluid ore-water pulp.

As soon as a compartment reaches the condition of full teeter, the discharge valve element 24 thereof is moved to open position to discharge at the desired rate.

As the teeter condition is reached, the increased density in the compartment causes the water to rise in the hydrostatic tube, and this increased pressure acts on the diaphragm of the pressure-responsive device 47. As soon as the density reaches the point at which the compartment is to operate, the adjustment on the pressure instrument 47 is set so that the contacts open or close at conditions corresponding substantially to the point on the potentiometer coil of the motor device 46 which will cause said motor device to hold the globe valve device 45 in the half-open position after the motor device 46 is connected to its source of current. The motor device 46 is then connected to its current source, and the compartment 15 is then under automatic control.

If for any reason the density rises in the teeter bed, the increased pressure will cause the motor device 46 to function so as to open the valve device 45 wider, thus allowing more water to enter the hydraulic chamber 17, which results in a decrease in density of the teeter bed in the sorting column thereabove. The increase in water will be just enough to return the teeter bed to the previously set density. If the density falls too low, the opposite action takes place and the associated globe valve element 45 is partially closed.

After the desired condition is established for each compartment and operation is set for automatic control, no further adjustments are required to continuously maintain this condition.

While certain specific models of control elements 46, 45 and 47 have been described above, it will be readily understood that any other equivalent models, other than those manufactured by the Minneapolis-Honeywell Regulator Company may be employed, and the invention is not limited to the use of the specific models described above.

Hydraulic classification of solid materials can only be efficiently accomplished in a machine which is provided with some means for maintaining a constant density. This has been accomplished in the past by varying the rate of discharge from the compartment. While this method works satisfactorily for some purposes, the varying rate of discharge is entirely unsuited for many other purposes or operations. For this reason, and primarily to satisfy the need for maintaining a constant rate of discharge, and at the same time for maintaining the density in the sorting column or teeter bed substantially constant, the device of the present invention has been devised.

While a specific embodiment of an improved hydraulic classified has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In a hydraulic classifier, a tank, partitions dividing said tank into successive compartments, weirs formed by the tops of said partitions connecting the upper portions of the compartments, whereby liquid containing material to be classified may flow from one compartment to the next, an inlet conduit at one end of the tank for admitting said liquid into the tank, a hydraulic chamber at the bottom of each compartment, a perforated partition member between each hydraulic chamber and the associated compartment, a discharge conduit in the bottom of each compartment, a manually controlled discharge valve in each discharge conduit, a hydraulic header, respective conduit means including a respective valve connecting said header to each hydraulic chamber density-responsive means in each compartment, and means operatively connecting said density-responsive means and last-named valve and controlling each lastnamed valve to control the supply of liquid from said header to each hydraulic chamber in accordance with the density of the material in the associated compartment.

2. In a hydraulic classifier, a tank, partitions dividing said tank into successive compartments, weirs formed by the tops of said partitions connecting the upper portions of the compartments, whereby liquid containing material to be classified may flow from one compartment to the next, an inlet conduit at one end of the tank for admitting said liquid into the tank, a hydraulic chamber at the bottom of each compartment, a perforated partition member between each hydraulic chamber and the associated compartment, a discharge conduit in the bottom of each compartment, a manually controlled discharge valve in each discharge conduit, a hydraulic header, means including a respective valve connecting said header to each hydraulic chamber, a vertical hydrostatic tube in each compartment, and respective electrically operated means controlled by the pressure in the tubes and operatively connected to the valves, said electrically operated means being arranged to automatically operate said last-named valves.

References Cited in the file of this patent UNITED STATES PATENTS 1,327,885 Stockton Jan. 13, 1920 2,410,637 Darby Nov. 5, 1946 2,646,169 Fox July 21, 1953 

